Timber is often sustainably sourced, but can the same be said for the rest of the materials used to build a home? Photograph: Niall Benvie/ Niall Benvie/CORBIS

1. Focus on the homes that leak the most heatThe energy company obligation (Eco) provided more than £1.3bn of funding to improve the homes that leak the most heat in the UK, but following complaints from energy companies this programme will soon just focus on cavity wall and loft insulation.

This is a mistake. Cavity wall and loft insulation often pay for themselves in less than two years so it hardly needs special funding. Instead, we are failing to deal with more than 7m homes that leak the most heat – of which half have residents in fuel poverty.

2. Use materials that are ethically and environmentally friendlySetting strict standards for which materials to use has hugely helped protect the environment in the past. Sustainably sourced timber is commonplace thanks to previous building standards and this has protected millions of acres of rainforest around the world.

The government is in the process of changing the standards of new build homes, but without implementing a strict standard for which materials should be used thousands of homes will be built without knowing if the base materials for steel, concrete and others were extracted and manufactured with human exploitation. The pollution caused in the manufacture of materials will also be ignored.

3. Ask about the environmental impactThe Climate Change Act calls for an 80% reduction in carbon by 2050. This challenge is mind blowing in its scale. It requires retro-fitting 25m homes – more than 13,000 homes a week – starting now.

If we are providing grants to a housing association to build homes, the association should have to disclose the environmental impacts they have. If a local authority is asking a contractor to insulate 2,000 homes, it should ask if their environmental impacts are measured and what they are doing to improve.

Too many organisations do not measure their environmental impact, but if their green credentials held sway when it came to winning contracts and grants, they would start taking this a lot more seriously.

4. Prepare for climate changeThe UK has 25m homes to retrofit, but few companies are considering how our changing weather should affect this.

We are in for a shock. Rain is getting heavier when it falls and summers are getting drier and, particularly in urban centres a good deal hotter. Often, homes and people in them cannot cope. The heatwave of 2003 lead to 2,000 deaths in the UK. Those building and retrofitting homes need to start thinking about how our homes need to adapt instead of just repeating the same measures they have used for years.